JP3372081B2 - White film - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a white film containing inorganic particles. More specifically, a metal laminating film that can be drawn, folded, etc. by laminating it on a metal plate, especially the most suitable metal laminating for can bodies such as beverage cans, food cans, can bottoms, can lids. A white film for laminating.

[0002]

2. Description of the Related Art Conventionally, a metal is generally coated to prevent corrosion, but a method for obtaining rust prevention without using an organic solvent has been developed. For example, (1)
A method in which biaxially oriented polyethylene terephthalate film is laminated via an adhesive layer of low melting point polyester and used as a can-making material (Japanese Patent Laid-Open No. 56-10451, Japanese Patent Publication No.
No. 192546), (2) Laminating an amorphous or low crystalline aromatic polyester film on a metal plate,
A method of using it as a can-making material (JP-A-1-192545, JP-A-2-57339, etc.), (3) laminating a low orientation polyethylene terephthalate film on a metal plate,
A method for use as a can-making material (Japanese Patent Laid-Open No. 64-22530, etc.) has been proposed.

However, the above method (1) has molding workability, particularly deep drawing workability, the method (2) has impact resistance, and the method (3) has (1).
Similar to the method (1), it is insufficient in terms of molding processability and is not practically used.

[0004]

Therefore, in view of the above problems of the present invention, the present invention is particularly suitable for metal bonding, which is excellent in moldability and impact resistance and can be sufficiently put to practical use. The purpose is to provide a film.

[0005]

The white film of the present invention for this purpose is a white film formed by diluting an inorganic particle highly filled resin A in which inorganic particles are densely packed with another resin B, and molding. At least a part of the diluted resin B is a resin B'having a viscosity of 0.03 or more plus the intrinsic viscosity of the resin A.
It consists of a thing characterized by consisting of.

The resins A, B, and B'in the present invention are not particularly limited, and examples thereof include nylon resin, polyester resin, polyolefin resin and the like. From the viewpoint of mechanical properties and moldability, polyester resins are both used. It is preferable that Of these, the resins A, B and B ′ are preferably made of a polyester copolymer. The copolymerized polyester is not particularly limited, but the following examples can be given as typical ones. Examples of acid components include aromatic dibasic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dodecadioic acid, dimer acid and cyclohexanedicarboxylic acid. Examples thereof include alicyclic dicarboxylic acid. Examples of the alcohol component include aliphatic diols such as ethylene glycol, diethylene glycol, butanediol, and hexanediol. These are used in combination of one or more. For example, as a preferred example, a polyester copolymer having 75 mol% or more of terephthalic acid as an acid component and 85 mol% or more of ethylene glycol as an alcohol component can be mentioned.

The resin A is densely packed with inorganic particles for whitening the film. As the inorganic particles for whitening, generally used titanium oxide particles can be used, but rutile type titanium oxide is particularly preferable. The average particle size of the inorganic particles is 0.05 to 1
μm is particularly preferably in the range of 0.1 to 0.5 μm. By using such rutile type titanium oxide particles,
The inorganic particles are uniformly and densely filled in the resin A.

The above-mentioned resin A highly filled with inorganic particles is diluted with the resin B to a predetermined particle concentration and then used for forming a white film. The particle concentration is not limited, but is 5 to 30% by weight, preferably 10 to 20% by weight.

At least a part of the diluted resin B is composed of a resin B'having a viscosity equal to or more than the intrinsic viscosity of the resin A plus 0.03. That is, the resin B has a wide viscosity distribution of a predetermined amount or more relative to the resin A by including such a resin B ′, and thus the mixture of the resin A and the resin B, and finally the resin B is finally obtained. The forming workability and impact resistance of the white film formed can be improved. On the other hand, since the resin A before dilution has a relatively lower viscosity than that, the inorganic particles for whitening can be more easily and uniformly dispersed, and higher filling can be achieved. In order to achieve the intrinsic viscosity difference of the present invention, the resin intrinsic viscosity difference used is 0.03
The above is usually taken, but when there is a difference in the heat resistance characteristics of the resins, the difference in the intrinsic viscosity of the resin before use does not necessarily have to be 0.03 or more.

The content of the above resin B'in the entire film is preferably 10% by weight or more. If the amount is less than this, the effect of improving the molding workability and impact resistance due to the inclusion of the resin B'cannot be sufficiently obtained.

The melting peak temperature of the resin A is preferably 0.5 ° C. or more lower than the melting peak temperature of the resin B ′. By controlling such a relationship of the melting peak temperature, good adhesiveness to, for example, a metal plate is secured mainly by the resin A component, and mechanical characteristics such as impact resistance are mainly secured by the resin B ′ or the resin B. Keeps good. That is, the adhesion and mechanical properties are well balanced.

The resin A as described above is diluted with the resin B containing the resin B'and used for forming a white film. The white film may be unstretched, uniaxially stretched, or biaxially stretched film, but for metal bonding, for example, metal used for can bodies such as beverage cans and food cans, can bottoms, and can lids. A biaxially stretched film is particularly preferable for the laminating film from the viewpoint of required mechanical properties.

The white film formed in this way can be used as a laminate laminated on a metal plate.
Examples of the metal plate include steel plates (tinplate, tin-free steel, etc.) and aluminum plates generally used for beverage cans and food cans. The surface of these metal plates may be appropriately subjected to organic or inorganic treatment.

Various lubricants may be added to the resins A and B of the present invention. The type of lubricant may be inorganic or organic. Suitable inorganic particles include agglomerated silica, spherical silica, alumina, titanium dioxide, calcium carbonate, barium sulfate, and zirconia. Examples of organic particles include silicone particles, crosslinked styrene particles, imide particles, and amide particles. The average particle size (by the sedimentation method) is 3.
It can be 0 μm or less, more preferably 1.5 μm or less, and most preferably 0.8 μm or less.

The method for producing the resin of the present invention, such as a polyester resin, is not particularly limited, but when the film of the present invention is laminated with a metal and the laminated product is used as a container, antimony is used as a polymerization catalyst. , Germanium can be mentioned. Resin A as a polymerization catalyst,
It is preferable that B is antimony and resin B'is used in combination such as germanium. If necessary, other additives,
For example, an antioxidant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a colorant, a pigment, a whitening agent and the like may be added.

The thickness of the white film of the present invention is 2
A range of up to 150 μm is suitable. Preferably 8 to 60
μm, and more preferably 12 to 40 μm.

Next, a typical production method of the present invention will be explained.
It is not limited to this. A resin A having a predetermined viscosity (usually 0.45 to 1.50 in intrinsic viscosity) is mixed with a resin B containing a resin B ′ having an intrinsic viscosity higher by 0.03 or more to be diluted, Both resins are appropriately lubricated and then dried to 400 ppm or less, preferably 80 ppm or less. The dry raw material is melted using an extruder and discharged in a sheet form from a die. When an extruder having degassed holes is used, drying may be omitted, or various additives may be added during the extruder. The melt-discharged sheet is once cooled on a cooling roll, and then stretched in the longitudinal direction in the range of 60 to 135 ° C. by 2.0 to 6.0 times, then 60 to 1
Stretched in the transverse direction 2.0 to 6.0 times in the range of 40 ° C,
Heat treatment is performed in the range of 0 to 240 ° C. while relaxing as necessary to obtain a desired white film.

[Measurement Method] (1) Deep Drawing Workability A predetermined film is attached to tin-free steel heated to 265 ° C., then cooled from the film side with a cooling roll and then water-cooled. The film-bonded metal plate thus obtained is cut into a disk having a diameter of 250 mm, and then the film surface is formed into an inner surface using a heat molding machine to form a drawing ratio of 1.3. The can thus obtained is subjected to a visual judgment and a rust prevention test. Rust resistance is 1%
NaCl water was put into a can, the can body was used as an anode, and the cathode was inserted in NaCl. It was judged that there was no appearance abnormality and the current value was 0.50 mA or less, and “O”, and the others were “X”.

(2) Impact resistance The deep-drawn can made under the conditions of (1) is filled with water and then sealed. After aging the canned goods and 50 pieces that have undergone retort treatment at 120 ° C for 30 hours, drop them on the floor inclined from the height of 1.2 m to 15 °, and then evaluate the rust prevention under the conditions described in (1). To do. The total number is 0.50 mA or less: ◯ 8 or more is 0.50 mA or less: Δ Other than that: ×, and it was determined that ◯ and Δ could be put to practical use.

(3) Intrinsic Viscosity The evaluation is made according to various literatures. For example, in the case of polyester resin, o-chlorophenol at 25 ° C. is used.

[0021]

【Example】

Example 1 As Resin A, the acid component was terephthalic acid (TPA) and isophthalic acid (IPA), and the alcohol component was ethylene glycol (EG) and diethylene glycol (DE).
Polyester P (T / I ·) containing 40% by weight of rutile type titanium oxide particles having an average particle size of 0.3 μm
EG / DEG) (IV = 0.52) was used. As the resin B, a resin B1 is used, and a substantially particle-free polyester (IV = 0.55) composed of terephthalic acid and isophthalic acid as an acid component and ethylene glycol and diethylene glycol as an alcohol component is used. Similarly, the acid component is terephthalic acid, isophthalic acid, and the alcohol component is ethylene glycol and diethylene glycol, and the intrinsic viscosity IV is 0.68, which is 0.13 higher than that of Resin A, and the melting peak temperature is 223.8 ° C. And a substantially particle-free polyester lower by 0.2 ° C. than that of Resin A was used.

The resin A is diluted with the resin B so that the rutile type titanium oxide particles have a predetermined concentration (resin A: resin B).
1: Resin B ′ = 40: 40: 20), which was supplied to an extruder, melt-extruded at 280 ° C., discharged from a die in a sheet form, and cast. This unstretched sheet is stretched at a stretching temperature of 1
It was longitudinally stretched at 02 ° C. and a stretching ratio of 3.0 times. The obtained uniaxially stretched film is introduced into a tenter and stretched at a stretching temperature of 110.
The film was transversely stretched at a temperature of ℃ and a stretching ratio of 3.1. The biaxially stretched film was once cooled, and then heat-fixed while being subjected to a relaxation treatment at 190 ° C., a transverse relaxation rate of 3% and a longitudinal relaxation rate of 1.2%.

Table 1 shows the characteristics of each resin and the characteristics of the film obtained together with the composition. As shown in Table 1, by satisfying the relationship specified in the present invention, excellent deep drawing workability and practically sufficient impact resistance were obtained.

Substantial Examples 2 to 5, Comparative Example 1 A white film was formed in the same manner as in Example 1 except that the composition and content of each resin, the intrinsic viscosity of the resin B ', and the melting peak temperature were changed, and the characteristics thereof. Was evaluated. The results are shown in Table 1. As shown in Table 1, when the requirements specified in the present invention were satisfied, the results that both the deep drawability and the impact resistance were satisfactory were obtained (Examples 2 to 5), but in Comparative Example 1 , The resin B ′ was not included, so that the impact resistance was particularly poor.

[0025]

[Table 1]

[0026]

As described above, according to the white film of the present invention, the high-inorganic-particle-filled resin A is diluted with the resin B containing the resin B'having a high intrinsic viscosity to obtain a white film. Therefore, especially when it is used for bonding with a metal, a film excellent in moldability such as deep drawing and impact resistance can be obtained.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 101/00 C08L 101/00 (72) Inventor Kunio Shibatsuji 1-1 1-1 Sonoyama, Otsu-shi, Shiga Toray Industries, Inc. Shiga Plant (56) References JP-A-61-250034 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/18 C08L 67/00-67/02

Claims (5)

(57) [Claims] 1. A white film formed by diluting a resin A highly filled with inorganic particles, which is densely packed with inorganic particles, with another resin B, wherein at least a part of the diluted resin B has an intrinsic viscosity of the resin A + 0. A white film comprising a resin B'having a viscosity of 0.03 or more. 2. The inorganic particles have an average particle size of 0.1 to 0.
The white film according to claim 1, which is a rutile type titanium oxide having a thickness of 5 µm. 3. The white film according to claim 1, which contains the resin B ′ in an amount of 10% by weight or more. 4. The white film according to claim 1, wherein the melting peak temperature of the resin A is lower than the melting peak temperature of the resin B ′ by 0.5 ° C. or more. 5. A laminate formed by laminating the white film according to claim 1 and a steel plate or an aluminum plate.